Read it through once

Perhaps on the nearer hills small streams may have cut a whole series of intersecting ravines in the black peat. They may be six to ten feet deep, and here and there the bleached white stones which underlie them are exposed. Now and then the "kuk-kuk-kuk" of an irate cock grouse, and much too frequently the melancholy squawking of the curlew, irritates the pedestrian as he stumbles over clumps of heather, plunges in and out of the mossy holes, or circumvents impossible peat-haggs.